I just finished playing today and I have to admit this is my personal fav so far even beating out Eternum as I love the characters waaaay too much. It's amazing how make me annoyed at nearly every character except Lucy and Akatsuki before making me fall in love head over heels with them. I am super smitten with Sarah and I really hope you don't fully forgone her original hairstyle for the cosplay one at the last scene. It's just preference really, and I love cute more than pretty. I am also impressed in how the subtle changes in Catherine's expression makes her from looking like a annoying bitch into a cute docile princess. All the characters interactions are so wholesome and really hits the spot for me, true to the name, super cosy. I truly can't wait to see what you're gonna cook up next and i hope it involves some more Sarah. Would also be nice if we can some of the girls who have their hair tied up throughout to let them down sometimes.
The dev has posted some hairstyle change attempts on discord in the past. Unfortunately, a lot of the characters' looks are tied to their hair, and some look like entirely new characters when it gets changed. So I would not expect it too often.
One reason it works for Sarah is because we know she does cosplay and styles her hair for it, so we are conditioned to still recognize her.
I'm not saying it will never happen, just that for many girls it may be too big of a change to easily incorporate.